Lost Communication With Fuel Injector Control Module
Your engine's main computer has lost the ability to talk to the fuel injector control module, like a phone losing signal with a connected device. Without this communication, the injectors can't receive proper commands to spray fuel into the cylinders.
The ECM continuously monitors CAN bus or hardwired communication signals to the fuel injector control module. It checks for valid signal presence, message acknowledgment, and data integrity at regular intervals. Loss of communication for a set duration triggers the fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| CAN Bus Signal Presence | Valid message received every 10-50 ms | No valid message for >500 ms |
| Module Acknowledgment | Module responds to ECM queries | No response or corrupted handshake |
Code U0105 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, U0105 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.